The present invention relates to continuous casting with twin rolls for manufacturing a thin band metal from a molten metal and, more particularly, to a manufacturing method and apparatus of a continuous casting machine which is suitable for manufacturing a thin sheet metal of excellent quality.
In, for example, Japanese Laid Open Patent Application No. 205655/1983, a continuous casting machine with twin rolls is proposed, wherein a molten metal is poured between the rotating twin rolls and cooled by the twin rolls so as to be formed into a solidified shell on the surface of each roll and compressed to a desired thickness at the narrowest gap or nip portion between the twin rolls. A pair of hydraulic pressure cylinders provide a compressive load which acts upon the twin rolls, and a difference between the compressive load on the drive side and an operation side of the twin rolls is compensated so as to enable a regulation of a hydraulic pressure in the hydraulic pressure cylinders in accordance with a difference of a roll gap between the drive side and operation side of the rolls. While this proposed arrangement is capable of providing a quality solid condition which is equal along the width direction of the sheet metal, a disadvantage resides in the fact that it is difficult and ineffective to prevent a leakage of the molten metal through a gap between the roll and a fixed plate, since a large separating force occurs when the solidified shells formed on the rolls are pressed by the twin rolls. Moreover, a change or alteration of the gap is caused between the rolls by virtue of an action of the separating force so that a gap between the rolls and fixed plate occurs. Thus, a continuous casting operation cannot be continued for a considerable length of time by virtue of the leaking of the molten metal through the gap between the rolls and the fixed plate.
The aim underlying the present invention essentially resides in providing a continuous casting machine with twin rolls wherein an arrangement is provided for enabling a prevention of a leaking of the molten metal between the rolls and fixed plates and achieving a continuous casting work so as to provide a high grade or high quality sheet metal.
In accordance with advantageous features of the present invention, a change or alteration of the gap between both rolls caused by the separating force is minimized during the pressing of the solidified shells in order to ensure the sealing between the rolls and the fixed plates.
It is also possible in accordance with further features of the present invention to enable a thickness of the sheet metal to be equal along the width direction thereof thereby ensuring the production of high quality sheet metal.
According to the present invention, a continuous casting machine is provided with twin rolls, with the casting machine including a housing, a container having a nozzle pouring molten metal, a pair of rotating rolls cooling the molten metal poured from the nozzle in order to form a solidified shell and compressing the solidified shell so as to enable a continuous manufacturing of a sheet metal of a desired thickness. A drive means is provided for rotating the rolls, with a plurality of bearing boxes being disposed in the housing for rotatably supporting the respective ends of each of the rolls. A pair of rigid members are disposed between the bearing boxes supporting the rolls for fixing the gap of the narrowest gap portion between the twin rolls and means are provided for providing an initial force or prestress in advance to the rigid members through the bearing boxes.
By virtue of the features of the present invention, it is possible to increase the rigidity of the casting machine with regard to the separating force for reducing the gap change between both rolls by the separating force and to prevent any leakage of molten metal between the rolls and the fixed plates so that it is possible to achieve a continuous casting operation for producing high quality sheet metal.